Optical properties of Al-doped a-Si:H films

Abstract

The effect of doping on a-Si:H film optical constants was studied. Evaporated films were doped with Al for making p-type material. The optical energy gap Eg decreased with increase in doping concentration. The Urbach parameter increased with doping. The refractive index decreased with increasing Al concentration showing a sharp rise in dispersion curve for p+ samples. The absorption coefficient increased with doping and the absorption edge shifted to lower energies.